Age-specific immunity to rotavirus infection and the risk of disease before and after rotavirus vaccine introduction in the United Kingdom: an observational, seroepidemiological study

BackgroundInfant rotavirus vaccination was introduced in the UK in July 2013, and was followed by a rapid reduction in rotavirus disease. We compare immunity to rotavirus in sera of age-stratified cohorts to assess the effect of vaccination on natural exposure to rotavirus. MethodsResidual serum samples were selected from a reference laboratory biobank based on age, and year of collection. Anti-rotavirus Immunoglobulin G (IgG) and IgA antibodies were measured using ELISA. We used censored linear spline regression models and anti-rotavirus IgA correlate of protection (CoP) thresholds to estimate immunity by age and vaccine eligibility (defined by date of birth). ResultsWe analysed serum from 1,200 individuals obtained between 2000 and 2019, of which 807 were vaccine-ineligible and 393 were vaccine-eligible. Among infants aged 3-11 months, a seven-fold increase in IgG levels was observed in the vaccine-eligible cohort (Geometric Mean Concentration [GMC], 1388.67 U/mL; 95% confidence interval [CI], 675.03-2856.78) compared to the vaccine-ineligible cohort (GMC, 198.54 U/ml; 95% CI, 71.31-552.78). Models showed increasing IgG and IgA antibody concentrations in the vaccine-ineligible cohort through childhood and into adulthood, but not in the vaccine-eligible cohort. The proportion of children <7 years with IgA[&ge;]160 U/ml, a proxy CoP against rotavirus disease, was lower among the vaccine-eligible population (adjusted odds ratio, 0.66; 95% CI, 0.48-0.91). ConclusionsThe introduction of rotavirus vaccination has reduced rotavirus disease burden but has disrupted the subsequent acquisition of naturally-acquired immunity. The impact of this on susceptibility to rotavirus disease in later life remains to be determined.